Starch-containing compositions for foods, such as confections, or non-foods, such as starch pastes and adhesives, comprising starch or starch-containing grains tend to undergo staling with time in consistency, palatability, and the like due to retrogradation of starch which had been gelatinized by heating when preserved in the presence of water in the composition, resulting in reduction of commercial value. Therefore, it is difficult to preserve these compositions for a long period of time or to transport them long distances.
Many attempts have been made in order to prevent or retard staling of the starch-containing compositions due to retrogradation of gelatinized starch contained therein. Conventionally proposed methods include addition of fatty acid monoglycerides, stearyl 2-lactate, lecithin, etc. to breads; addition of lecithin, fatty acid monoglycerides or natural gum rubber, etc. to confections, e.g., sponge cakes, crepes, etc.; addition of sucrose, dextrin, amylases, sorbitol, various starch sugars (syrups) or natural gum rubber to Japanese-style confections, e.g., rice cakes, rice pastes, etc. addition of amylases or surface active agents to boiled rice; and the like as described in U.S. Pat. Nos. 4,291,065 and 4,320,151. Addition of these additives is effective to some extent depending on the characteristics of the respective additive. In the field of non-food starch-containing compositions, e.g., starch pastes and adhesives, glycerin, formamide, etc. have been used as additives for preventing cracking due to drying or starch retrogradation.
However, the effects achieved by these conventional additives are still insufficient to prevent deterioration of the starch-containing compositions, and development of an additive which produces greater effects has been demanded.
Further, glycerin which has been conventionally added to non-food starch-containing compositions is a dangerous material to have about, and formamide is anesthetic to humans. Therefore, use of these additives requires special care for safety and hygiene.